René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"test_runner: node:coverage ignore comments exclude DA but leave BRDA in lcov output","articleBody":"### Version\n\nv24.13.0\n\n### Platform\n\nDarwin 24.6.0 (macOS)\n\n### Subsystem\n\ntest_runner\n\n### What steps will reproduce the bug?\n\n1. Create a file with a branch and `/* node:coverage ignore next */` comment:\n\n```javascript\n// src/example.js\nfunction getValue(condition) {\n  if (condition) {\n    return 'truthy';\n  }\n  /* node:coverage ignore next */\n  return 'falsy';\n}\n\nmodule.exports = { getValue };\n```\n\n2. Create a test that only covers the truthy branch:\n\n```javascript\n// test/example.test.js\nconst { describe, it } = require('node:test');\nconst assert = require('node:assert');\nconst { getValue } = require('../src/example.js');\n\ndescribe('getValue', () =\u003e {\n  it('should return truthy when condition is true', () =\u003e {\n    assert.strictEqual(getValue(true), 'truthy');\n  });\n});\n```\n\n3. Run with coverage:\n\n```bash\nnode --experimental-test-coverage --test-reporter=lcov --test-reporter-destination=coverage/lcov.info --test test/example.test.js\n```\n\n4. Examine the generated `lcov.info`\n\n### How often does it reproduce? Is there a required condition?\n\nAlways reproducible.\n\n### What is the expected behavior? Why is that the expected behavior?\n\nThe `/* node:coverage ignore next */` comment should exclude **both**:\n- The DA (line coverage) entry for the ignored line\n- The BRDA (branch coverage) entry for the branch leading to the ignored code\n\nThis is the expected behavior because:\n1. The purpose of ignore comments is to exclude code from coverage calculations\n2. `c8` (which also uses V8 coverage) correctly handles this by marking both DA and BRDA as covered for ignored lines\n\n### What do you see instead?\n\n- **DA**: Line 6 (`return 'falsy';`) is correctly excluded from the lcov output\n- **BRDA**: Branch entry remains as uncovered: `BRDA:4,2,0,0`\n\n```\nBRDA:1,0,0,1\nBRDA:1,1,0,1\nBRDA:4,2,0,0    \u003c-- This branch should be excluded but remains as uncovered\nBRF:3\nBRH:2           \u003c-- Only 2 of 3 branches hit (66.67%)\nDA:1,1\nDA:2,1\nDA:3,1\nDA:4,1\nDA:5,0\nDA:7,1          \u003c-- DA:6 is missing (correctly excluded)\n...\n```\n\nThis causes branch coverage to report 66.67% instead of 100%, which impacts CI/CD pipelines that enforce branch coverage thresholds.\n\n### Additional information\n\n**Comparison with c8:**\n\nUsing `c8` with `/* c8 ignore next */` on the same code structure produces the correct result:\n\n```\nDA:5,1          # Line marked as covered (ignored)\nDA:6,1          # Line marked as covered (ignored)\nBRDA:5,2,0,1    # Branch marked as covered (ignored)\nBRF:3\nBRH:3           # All 3 branches \"hit\" (100%)\n```\n\n**Minimal reproduction repository:**\n\nhttps://github.com/tobigumo/node-coverage-brda-bug\n\n```bash\ngit clone https://github.com/tobigumo/node-coverage-brda-bug.git\ncd node-coverage-brda-bug\nnpm install\nnpm run test\n# Compare coverage/lcov-native.info (Node.js native - has bug) with coverage/lcov.info (c8 - correct)\n```","author":{"url":"https://github.com/tobigumo","@type":"Person","name":"tobigumo"},"datePublished":"2026-01-30T11:53:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/61586/node/issues/61586"}